In THIS post Nick (@nmp) spoke of a vapouriser for his Juwel stove with a jet orifice worn to a cavernous 0.55mm. He attempted to peen it down and had some success, but reported the flame was lop-sided and his photo showed it was still running fuel-rich. Nick took me up on my offer to repair it using the technique I devised of silbrazing a length of hypodermic needle in the jet to correct its off-centre output and reduce it to 0.23mm, the consensus view of what it should be. Certainly that’s the correct jet orifice diameter for Nos. 96 and 100 stove ‘lipstick’ vapourisers, so it seemed a safe bet. He asked me to post details of the repair here to show how it was done. I took delivery of the vapouriser yesterday but spent the morning today in Southport looking for the sea. A good walk, a considerable length of pier and plenty of pools from overnight rains but as is usual at Southport (high or low tide, it makes little difference) the sea was something like a mile away over soggy mud flats so I didn’t get to it, or even anywhere near enough to hear it. So, this afternoon, the vapouriser repair. Nick’s peening had left the jet hole a loose fit on a 0.32mm pricker. Here’s the hypodermic needle I cut the insert from, approximately a 15mm length, subsequently trimmed down in the finished repair to 2mm or so protruding on the inside of the vapouriser and flush with a silbraze ‘skim’ on the outside, so about 1.5mm bonded with the thickness of vapouriser metal at its tip including the silbraze ‘skim’. With a 0.23mm bore and an outer diameter of 0.45mm I would usually rotate the needle’s angled point in the existing jet orifice to ream its own diameter to install. Because Nick had spoken of the burner flame being lop-sided however, I used a 0.45mm micro-drill bit in a power drill rather than the reaming technique to ensure that the resulting hole was aligned with the centreline of the vapouriser. Here’s the needle inserted in the hole to confirm it’s properly aligned, prior to cutting off the plastic syringe connector and trimming off the bevelled tip of the needle on the inside. Silbrazing done. Before cleaning off the flux, which leaves a hard glaze, and trimming off the excess needle. Video to show the insert’s alignment with the vapouriser’s centreline, so the flame output should be aligned also. Here I’m boiling the component to dissolve the flux residue. Trimmed and polished. Pricker is now a 0.23mm one, a clearance fit. I should add, I don’t have a Juwel to try out the vapouriser on, so I’ll leave it to Nick to post details of the end result. Oh, and to replace the brass gauze in the vapouriser - tricky given that narrow-bore inlet. John
Hi @presscall excellent outstanding work, i am over the moon with the work you did on my two lipstick burners, i swear by this system being the best solution, peening is a good simple way of repairing i have done one or two few years back with reasonable success, but very easy to get a lop sided flame as above, and another point i love about this system is the finished result is so neat and the burner looks untouched and as good as it left the factory
@presscall Great stuff John looks perfect, I will post flame shots once it’s got a gauze in. I suppose the gauze does to have to be to tightly packed ? I will PM with address etc thanks so much! Lovely clear report of your excellent work the maestro strikes again! Gratefully Nick
@nmp I’ve inserted the brass gauze in the vapouriser Nick. Four rolls By inserting four slim rolls rather than trying to bundle in a bulkier wad, I had in mind what I discovered fulfilling the same role in this Punker alcohol stove’s vapouriser, a bundle of brass rods. I hope to get the vapouriser off to you today. John
You got all 4 rolls in? Optical illusion. It doesn't look like they would fit. Great work, as always.
I did Ken. Three slid in without bother, the fourth snagged a bit on the others when 3/4-way in and I prodded it home with a steel rod. This ‘96’ vapouriser is of slightly smaller diameter than the Juwel’s but could accommodate four of those gauze rolls too I’d say. John
Excellent John you like a challenge. When I packed it last time I basically rammed it in in small bits it was an absolute bugger to get out again before a I sent it off to you. For everyone’s information the connecting thread on a Juwel No 6 is much smaller than that of a No. 96so the hole to flit the gauze into is about 8mm maybe? The original burner tube is referenced by Juwel (Gustav Barthel) as a cartridge to be disposed of once choked with carbon, so a non serviceable item, unless your a stovie! The base of the burner was braised (?) on once the gauze was in place? Excellent job John flame shots to follow. Nick
@presscall The eagle has landed! Nice flame pattern. Lovely job John thanks so much. It’s a bit of a game to light and seems to want plenty of heat before it stays alight properly. But it gives off reasonable heat once running. this fettle involved stopping a leak at the tank seam, new washers, a new 3D printed Bernie dog flame plate (ouch) and a fantastic repair of the vapouriser by John @presscall .
@nmp Ho Nick, if you didn’t already, I would make a dunk test to see if the tank is 100% pressure tight… renewing the NRV pip on Juwel 6 is not always straight if Viton is used instead of cork. @presscall great work as usual Nicola
@presscall that was after a few pumps maybe not really pumped up, it doesn’t get much more output than that. I will have another test tomorrow . Thanks @Nicola Francesco Elia for the expert advice I think a few more tests maybe needed. I did a dunk test when dealing with the leaky bottom seam and no air came out but it would leak paraffin or water when put under pressure how strange ? No apparent problems with NRV. Despite replacement of pip with Viton.
As suspected, flame can be really affected also by minor leaks. It’s incredible how paraffin finds its way out easily than air… this happens more than often. Nicola
